The traditional stirling engine is generally composed of a shifting air cylinder as well as a heater and a cooler arranged at two ends of the shifting air cylinder. The shifting air cylinder is internally provided with a shifting air piston to divide the shifting air cylinder into a heating chamber and a cooling chamber. The two chambers are connected through a regenerative heating passage. However, the structure design of the existing stirling engine is unreasonable; when a power piston is pushed to act through heating and expanding, a part of heat energy enters a cooling end through a regenerator, and the heat energy is neutralized, which leads to the restriction on the efficiency of the stirling engine, so that the stirling engine cannot be popularized for using.